1997 AUDI A4 ABS

24-94

Engine speed (RPM) signal, checking


Notes:
The RPM signal is routed from the ECM to
various electronic systems (e.g. automatic
transmission, ABS, etc.). The RPM signal is
monitored by the different electronic systems.
Carry out the following check only if the
tachometer (in the instrument cluster) is
inoperative, or if the A/C compressor is not
running.

- Connect VAG 1367 engine-tester to tachometer
using wiring diagram.

- Connect VAG 1367 engine-tester signal wire
(green terminal) to instrument cluster RPM
terminal and A/C control module RPM terminal
(connector remains connected).

- Start engine and let idle.

RPM must be displayed again
If the specified value is obtained, the malfunction
is in instrument cluster or on A/C control module.
If the RPM is not displayed on VAG 1367 engine-
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24-109

Rough road condition signal, checking


ABS control module with ABS/EDL

Notes:

Misfires can result in malfunctions such as
"Combustion misfire" being recorded in DTC
memory due to road wheel malfunctions.
If the ABS control module recognizes a free
turning wheel, it generates a rough road signal.
If the Engine Control Module (ECM) recognizes
the rough road signal, misfire recognition is
switched off in the ECM.
The rough road signal is created to check
whether DTC 18014 "Rough Road Spec Engine
Torque ABS-SG Electrical Malfunction" is
stored in DTC memory. The "Combustion
misfire" malfunction results from this signal and
can be ignored.
The rough road signal is monitored by the
ECM.

Checking requirement

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Control module coding OK page 01
-247
.

Checking

- Switch ignition OFF.

- Connect VAG 1598/19 test box to ECM harness
connector page 01
-255
.

- Check signal wire for open or short circuit
between ECM and ABS control module, using
wiring diagram.
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24-110

- Find and eliminate open or short circuit; repair
as necessary.
If wiring is OK:

- Replace ABS control module.
If the ABS control module is OK, but the
malfunction is still occurring:

- Replace ECM page 01
-265
.

ABS control module with ABS/EDL/ASR

Notes:

The torque signal is monitored by the
"Automatic Traction Control" Control Module
and by the ECM.

Repair Manual, Brake System On Board
Diagnostic (OBD), Repair Group 01


Vehicles with automatic traction control (ASR)
can be recognized by the ASR indicator light in
the instrument cluster or by control module
identification displayed during the ABS On
Board Diagnostic program sequence.
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pair&id=AUDI.B5.FU01.24.25